JP3343613B2 - Writing implement - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a writing instrument having a writing tip protected by a detachable cap.

[0002]

2. Description of the Related Art Conventionally, a writing instrument of this type is configured such that a circular inner surface of a cap is fitted to and removed from a circular outer peripheral surface of a writing end of a barrel. By the way, in the above-mentioned conventional writing implement, when the cap is retracted in the axial direction with respect to the barrel and then removed, the fitting between the barrel and the cap becomes too strong due to dimensional variation, and the cap may be difficult to remove. Also, if the cap that is tightly fitted due to the above-mentioned cause is forcibly removed, the cap retreats abruptly, and the pressure around the pen tip momentarily becomes negative pressure. Was causing it. Therefore, in order to solve the above problem, a ridge-shaped projection is provided on the outer periphery of the writing end of the barrel, and a valley-shaped concave groove is provided on the inner peripheral surface of the cap. There has been proposed a configuration in which a concave groove is pushed up on a side surface of a mountain-shaped projection on the outer periphery of a barrel, and a cap is separated from the barrel (see Japanese Utility Model Application Laid-Open No. 61-81986).

However, in the latter conventional example, when the tip angle of the mountain-shaped projection is reduced, a large rotational force is required when removing the cap, so that it is difficult to remove the cap. When the tip angle is increased, when the cap is fitted to the tip of the barrel, the frictional force between the valley-shaped concave groove and the mountain-shaped projection becomes large, and the cap is difficult to fit.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a writing instrument in which a cap can be easily fitted and removed.

[0005]

As a technical means of the present invention for solving the above-mentioned problems, a first aspect of the present invention is to provide an approximately isosceles triangular chevron portion at an outer periphery fitting portion on a tip end of a shaft cylinder. Have
In addition, the fitted portion on the inner surface of the cap has a substantially isosceles triangular valley-shaped portion that follows the angled portion, and the angled portion is circumferentially arranged by being symmetrically arranged with respect to the axis. Each of the valleys is formed at predetermined intervals in the direction, and the valleys are formed at four equally spaced intervals to engage with the chevron, and the height from the bottom to the top of the chevron and the height The depth of the trough is approximately πR / R, where R is the radius of the outer periphery fitting portion.
The angled portion is a value calculated by the mathematical formula 4, and the sharp portion touches the hand when gripping the writing end of the barrel during writing.
Curve the top so that you don't feel any damage
It is characterized by being formed by . According to the above technical means, when removing the cap, if the cap is rotated in the circumferential direction of the barrel, the valley portion is pushed up to the chevron, and the cap is gradually separated from the barrel. Also, when the cap is fitted to the tip of the barrel, if the cap is placed over the tip of the barrel and pressed, the slope of the chevron and the slope of the valley are in sliding contact with each other, so that the cap is slightly rotated and fitted. The inventor of the present application, when fitting and removing the cap as described above, the diameter of the outer circumferential fitting portion of the barrel, the relationship between the height of the chevron and the depth of the trough, when the cap is fitted. It is known that the force of both the case and the case of removal changes. The height from the bottom to the top of the chevron and the depth of the trough are set to values calculated by a formula of approximately πR / 4, where R is the radius of the outer peripheral fitting portion on the tip end of the barrel. In, it was experimentally confirmed that both the force adjustments were the same, and that it was extremely easy to remove and insert the cap,
The present invention has been completed. Since the chevron is formed in a substantially isosceles triangular shape, the force does not change depending on the rotation direction of the cap. Furthermore, by the same technical means
If the top of the chevron is curved,
Sometimes the sharp tip touches the hand when gripping the writing end of the barrel.
It does not feel any damage and has a good grip feeling.
You.

According to a second aspect, the cap is provided on the front side.
And a large-diameter portion on the rear side of the large-diameter portion.
The outer peripheral surface at the front end side of the
It is characterized by being.

[0007]

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of a writing instrument according to the present invention. This writing implement is a felt-tip pen provided with a cap 20 that can be fitted to and detached from the distal end side of the writing implement main body A. The writing implement main body A is configured to discharge ink impregnated in the batting in the barrel 10 from the pen tip 1 at the tip of the barrel 10 by capillary action.

The shaft cylinder 10 has a chevron 11 at an outer peripheral fitting portion 10a on the writing tip side for fitting the cap 20.

The chevron 11 has an R-chamfered curved surface 1 at the top.
It has a substantially isosceles triangular shape in a plan view formed with 1a, and its side surface protrudes in the centrifugal direction from the outer peripheral fitting portion 10a on the tip end side of the barrel 10 and is arranged symmetrically with respect to the axis of the barrel 10. Are formed at predetermined intervals in the circumferential direction. The angle 11 is defined by the height h from the bottom to the top, and the radius of the outer fitting portion 10a of the barrel 10 by R.
Is set to a value calculated by a formula of approximately πR / 4. In addition, the height h to the top mentioned above means the height to the intersection of two oblique sides as shown in FIG.
The reason why the two are arranged symmetrically with respect to the axis of the shaft cylinder 10 is to maintain the balance of the force applied when the cap 20 is removed.

The cap 20 has a fitted portion 20a which can be fitted to and removed from the outer fitting portion 10a of the barrel 10 at the rear end side of the inner circumferential surface thereof.
And a valley portion 21 that engages with the chevron portion 11 is formed in the fitted portion 20a.

The valleys 21 are formed in a substantially isosceles triangular shape following the slopes of the chevron 11 by recessing the inner wall on the rear end side of the cap 20 and are continuously spaced at equal intervals in the circumferential direction. Are arranged so that every four of them are engaged with the chevron 11. The valley 21 has a depth h up to the bottom of the valley, similarly to the chevron 11, and the radius of the outer fitting portion 10a of the barrel 10 is R, and is calculated by a formula of approximately πR / 4. Set to a value.

According to the writing instrument having the above-described structure, FIG.
As shown in (a) to (d), when the cap 20 is removed, if the cap 20 is rotated in the circumferential direction of the barrel 10,
The valley 21 of the cap 20 is pushed up by the chevron 11 of the barrel 10, and the cap 20 is separated from the barrel 10.
Also, when fitting the cap 20 to the barrel 10, FIG.
The states shown in (a) to (d) are in the reverse order. When the cap 20 is put on the tip of the barrel 10 and pressed, the slope of the chevron 11 and the slope of the valley 21 are slid in contact with each other.
0 is inserted while being slightly rotated.

When the cap 20 is fitted and removed as described above, the cap 20 is fitted according to the relationship between the diameter of the outer peripheral fitting portion 10a of the barrel 10 and the height of the chevron 11 and the depth h of the valley 21. The amount of force between the case and the case of removal changes. In the writing instrument according to the present embodiment, the height from the bottom to the top of the chevron 11 and the depth h of the trough 21 are approximately πR, where R is the radius of the outer periphery fitting portion 10a at the tip end of the barrel 10. By setting the value to be calculated by the formula of / 4, the force adjustment in both the case where the cap 20 is fitted and the case where the cap 20 is removed are set to the same level, and the fitting and disengaging of the cap 20 are both facilitated.

That is, when the denominator of the above equation is smaller than 4, the height from the bottom to the top of the chevron 11 and the depth h of the valley 21 are increased, and
1 and the inclination angle θ of the valley 21 are also increased. Accordingly, when the cap 20 is removed, the frictional force between the inclined surface of the chevron 11 and the inclined surface of the valley 21 increases.
The rotational force for rotating 0 increases. On the other hand,
When the cap 20 is fitted, the frictional force between the inclined surface of the chevron 11 and the inclined surface of the valley 21 decreases, and the cap 2
The force for pushing 0 in the axial direction is reduced, and a firm fit is not felt.

When the denominator of the above equation is a value larger than 4, the height from the bottom to the top of the chevron 11 and the depth h of the valley 21 are reduced, and
1 and the inclination angle θ of the valley 21 are also reduced. Accordingly, when the cap 20 is removed, the frictional force between the inclined surface of the chevron 11 and the inclined surface of the valley 21 is reduced.
The rotation force for rotating 0 becomes smaller and the cap 2
0 easily comes off immediately. On the other hand, when the cap 20 is fitted, the frictional force between the inclined surface of the angled portion 11 and the inclined surface of the valley portion 21 increases, and the force for pushing the cap 20 in the axial direction increases.

In this embodiment, since the top of the chevron 11 of the barrel 10 is the curved surface 11a, when the cap 20 is turned off, the turning force at the start of turning is relatively small.
That is, when both the top of the chevron 11 and the bottom of the trough are sharply formed, the engaging force due to the engagement of the sharp portions is strong, and the rotational force at the start of rotation is large. However, if one of them is a curved surface, the rotational force may be small.

The writing implement of the present embodiment was evaluated with respect to 100 clerks. As a result, compared with the case where the denominator of the formula πR / 4 was set to 3 and 5, 9 said that it was easy to remove the cap
Seven people, three people said that it did not change much. That is, the result is that most people easily feel the disengagement.

Although the above embodiment describes the case where the present invention is applied to a single-head type writing instrument, it is needless to say that the present invention may be applied to a double-head type writing instrument.

[0020]

According to the present invention, the adjustment of the force when fitting the cap and the adjustment of the force when removing the cap are the same, and the balance is good, and the fitting and disengaging of the cap is very easy. In addition, since the two chevron portions are formed substantially symmetrically with respect to the axis, the minimum number of chevron portions can maintain stability when the cap is removed. Moreover,
Since every other valley portion is fitted to and detached from the valley portion, the dimensional accuracy of the valley portion and the valley portion is roughly reduced as compared with engaging all the valley portions and all the valley portions. can do.
In addition, since four valleys are formed at equal intervals, the two chevrons are fitted into any two of the four valleys when the cap is fitted. Therefore, the positioning between the chevron and the trough is easy and the operability is excellent. Further, when the cap is fitted, an empty valley without fitting is interposed between the valleys into which the valleys are fitted. Normally, caps are the resin molded article, fitting because
Although some elastic deformation by the engaging force upon the outer Mr. elastic deformation of the cap during its is absorbed by the empty valley portion. Therefore, the engaging force between the chevron and the trough is reduced, and the cap can be easily removed from the cap. Change
In addition, since the top of the chevron is formed with a curved surface, the turning force at the start of rotation when removing the cap is small, it is easier to remove the cap, and when gripping the writing end side of the barrel at the time of writing Grip feeling can be improved.

[Brief description of the drawings]

1A and 1B show an example of a writing instrument according to the present invention, in which FIG. 1A is a plan view of a main part showing a state in which a cap is fitted to a writing instrument body, and FIG. 1B is a state in which a cap is removed from the writing instrument body; The writing instrument main body is shown in a plan view, and the cap is shown in a longitudinal sectional view.

FIGS. 2A and 2B are development views showing a fitting state of a chevron part and a trough part when a cap is removed from a writing instrument main body, and FIGS.
(D) shows a state in which the chevron and the trough gradually depart from the fitted state.

[Explanation of symbols]

 10: Shaft tube 10a: Outer periphery fitting portion 11: Angle portion 11a: Curved surface 20: Cap 20a: Fitted portion 21: Valley shape portion A: Writing implement body

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B43K 3/00 B43K 23/08-23/12 B65D 35/44-35/54 B65D 39/00-55 / 16

Claims (2)

(57) [Claims] 1. An outer peripheral fitting portion on a writing end side of a shaft cylinder is substantially equal to two or more.
It has a triangular-shaped triangular shape and the inner surface of the cap.
The fitted portion has a substantially isosceles triangular valley shaped portion that follows the chevron, and each of the chevrons is arranged symmetrically with respect to the axis so that each is predetermined in the circumferential direction. Formed at intervals,
The four valleys are formed at equal intervals so as to engage with the valleys, and the height from the bottom to the top of the valleys and the depth of the valleys are determined by the outer fitting portion. preceding the radius is a value calculated by the formula substantially .pi.R / 4 as R, when the angular portion, which holds the barrel writing tip side at the time of writing
No sharp parts touch your hands and feel pain
Writing implement characterized in that the top is formed as a curved surface 2. The cap according to claim 1 , wherein the front small-diameter portion and the
An outer peripheral surface on the front end side of the large diameter portion
2. The writing instrument according to claim 1 , wherein the swelling portion is expanded in a curved shape when viewed from the side .